Headland or loch (4)
I believe the answer is:
ness
This clue is a double definition.
'headland' is the first definition.
(both can mean a promontory)
'loch' is the second definition.
(Loch Ness in Scotland)
'or' acts as a link.
(Other definitions for ness that I've seen before include "Scottish loch - headland" , "Headland, promontory" , "Scottish lake with traditional monster" , "Headland, cape" , "Eliot -, led effort against Al Capone; Scots loch" .)